In recent years, it is becoming more common for new engine designs to have their cylinders offset from their crankshaft axes. In other words, each cylinder is positioned with its bore axis slightly offset from the center line of the crankshaft. Engines having these cylinder configurations are referred to as “offset cylinder”, “crank offset”, or “Désaxé” engines.
Typically, a reference to an “offset cylinder” engine is to an internal combustion automotive or motorcycle engine. The offset configuration can have the advantages of increased torque on the crankshaft, as well as reduction in frictional forces between the piston and cylinder.
Experimental testing to determine the effect of cylinder offset is problematic. For a production engine, a new cylinder block casting is needed for each value of offset to be evaluated. Furthermore, with each different offset, to maintain the same compression ratio, either the connecting rod length or the cylinder block height must be adjusted. Adjusting the connecting rod length complicates the testing, and adjusting block height is often impractical.